The yield of a chemical process is being studied. The two most important variables are thought to be the pressure and the temperature. Three levels of each factor are selected, and a factorial experiment with two replicates is performed. The yield data follow: Temperature Pressure
200 215 230
150 90.1 90.5 89.9
90.3 90.6 90.1
160 90.5 90.8 90.4
90.7 90.9 90.1
170 90.4 90.7 90.2
90.2 90.6 90.4

(a) Analyze the data and draw conclusions. Show your ANOVA table. Use α = 0.05.
(b) Prepare and show appropriate residual plots and comment on the model’s adequacy.
(c) Under what conditions would you operate this process?

What precautions should you take to prevent injuries when dealing with heavy loads?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false